// tutorial06.c
// A pedagogical video player that really works!
//
// This tutorial was written by Stephen Dranger (dranger@gmail.com).
//
// Code based on FFplay, Copyright (c) 2003 Fabrice Bellard, 
// and a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de)
// Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1
//
//
//
// Updates tested on:
// Mac OS X 10.11.6
// Apple LLVM version 8.0.0 (clang-800.0.38)
//
// Use 
//
// $ gcc -o tutorial06 tutorial06.c -lavutil -lavformat -lavcodec -lswscale -lz -lm `sdl-config --cflags --libs`
//
// to build (assuming libavutil/libavformat/libavcodec/libswscale are correctly installed your system).
//
// Run using
//
// $ tutorial06 myvideofile.mpg
//
// to play the video.

#include <libavcodec/avcodec.h>
#include <libavformat/avformat.h>
#include <libavformat/avio.h>
#include <libswscale/swscale.h>
#include <libavutil/avstring.h>
#include <libavutil/time.h>

#include <SDL.h>
#include <SDL_thread.h>

#ifdef __MINGW32__
#undef main // Prevents SDL from overriding main().
#endif

#include <stdio.h>
#include <math.h>

#define SDL_AUDIO_BUFFER_SIZE 1024
#define MAX_AUDIO_FRAME_SIZE 192000

#define MAX_AUDIOQ_SIZE (5 * 16 * 1024)
#define MAX_VIDEOQ_SIZE (5 * 256 * 1024)

#define AV_SYNC_THRESHOLD 0.01
#define AV_NOSYNC_THRESHOLD 10.0

#define SAMPLE_CORRECTION_PERCENT_MAX 10
#define AUDIO_DIFF_AVG_NB 20

#define FF_ALLOC_EVENT (SDL_USEREVENT)
#define FF_REFRESH_EVENT (SDL_USEREVENT + 1)
#define FF_QUIT_EVENT (SDL_USEREVENT + 2)

#define VIDEO_PICTURE_QUEUE_SIZE 1

#define DEFAULT_AV_SYNC_TYPE AV_SYNC_VIDEO_MASTER

typedef struct PacketQueue {
	AVPacketList *first_pkt, *last_pkt;
	int nb_packets;
	int size;
	SDL_mutex *mutex;
	SDL_cond *cond;
} PacketQueue;


typedef struct VideoPicture {
	SDL_Overlay *bmp;
	int width, height; // Source height & width.
	int allocated;
	double pts;
} VideoPicture;

typedef struct VideoState {
	AVFormatContext *pFormatCtx;
	int videoStream, audioStream;
	
	int av_sync_type;
	double external_clock; // External clock base.
	int64_t external_clock_time;
	
	double audio_clock;
	AVStream *audio_st;
	PacketQueue audioq;
	AVFrame audio_frame;
	uint8_t audio_buf[(MAX_AUDIO_FRAME_SIZE * 3) / 2];
	unsigned int audio_buf_size;
	unsigned int audio_buf_index;
	AVPacket audio_pkt;
	uint8_t *audio_pkt_data;
	int audio_pkt_size;
	int audio_hw_buf_size;
	double audio_diff_cum; // Used for AV difference average computation.
	double audio_diff_avg_coef;
	double audio_diff_threshold;
	int audio_diff_avg_count;
	double frame_timer;
	double frame_last_pts;
	double frame_last_delay;
	double video_clock; // PTS of last decoded frame / predicted pts of next decoded frame.
	double video_current_pts; // Current displayed pts (different from video_clock if frame fifos are used).
	int64_t video_current_pts_time;  // time (av_gettime) at which we updated video_current_pts - used to have running video pts.
	AVStream *video_st;
	PacketQueue videoq;
	
	VideoPicture pictq[VIDEO_PICTURE_QUEUE_SIZE];
	int pictq_size, pictq_rindex, pictq_windex;
	SDL_mutex *pictq_mutex;
	SDL_cond *pictq_cond;
	
	SDL_Thread *parse_tid;
	SDL_Thread *video_tid;
	
	char filename[1024];
	int quit;
	
	AVIOContext *io_context;
	struct SwsContext *sws_ctx;
} VideoState;

enum {
	AV_SYNC_AUDIO_MASTER,
	AV_SYNC_VIDEO_MASTER,
	AV_SYNC_EXTERNAL_MASTER,
};

SDL_Surface *screen;

// Since we only have one decoding thread, the Big Struct can be global in case we need it.
VideoState *global_video_state;

void packet_queue_init(PacketQueue *q) {
	memset(q, 0, sizeof(PacketQueue));
	q->mutex = SDL_CreateMutex();
	q->cond = SDL_CreateCond();
}

int packet_queue_put(PacketQueue *q, AVPacket *pkt) {
	AVPacketList *pkt1;
	if (av_packet_ref(pkt, pkt) < 0) {
		return -1;
	}
	pkt1 = av_malloc(sizeof(AVPacketList));
	if (!pkt1) {
		return -1;
	}
	pkt1->pkt = *pkt;
	pkt1->next = NULL;
	
	SDL_LockMutex(q->mutex);
	
	if (!q->last_pkt) {
		q->first_pkt = pkt1;
	}
	else {
		q->last_pkt->next = pkt1;
	}
	q->last_pkt = pkt1;
	q->nb_packets++;
	q->size += pkt1->pkt.size;
	SDL_CondSignal(q->cond);
	
	SDL_UnlockMutex(q->mutex);
	return 0;
}

static int packet_queue_get(PacketQueue *q, AVPacket *pkt, int block) {
	AVPacketList *pkt1;
	int ret;
	
	SDL_LockMutex(q->mutex);
	
	for (;;) {
		
		if (global_video_state->quit) {
			ret = -1;
			break;
		}
		
		pkt1 = q->first_pkt;
		if (pkt1) {
			q->first_pkt = pkt1->next;
			if (!q->first_pkt)
				q->last_pkt = NULL;
			q->nb_packets--;
			q->size -= pkt1->pkt.size;
			*pkt = pkt1->pkt;
			av_free(pkt1);
			ret = 1;
			break;
		} else if (!block) {
			ret = 0;
			break;
		} else {
			SDL_CondWait(q->cond, q->mutex);
		}
	}
	SDL_UnlockMutex(q->mutex);
	return ret;
}

double get_audio_clock(VideoState *is) {
	double pts;
	int hw_buf_size, bytes_per_sec, n;
	
	pts = is->audio_clock; // maintained in the audio thread.
	hw_buf_size = is->audio_buf_size - is->audio_buf_index;
	bytes_per_sec = 0;
	n = is->audio_st->codec->channels * 2;
	if (is->audio_st) {
		bytes_per_sec = is->audio_st->codec->sample_rate * n;
	}
	if (bytes_per_sec) {
		pts -= (double)hw_buf_size / bytes_per_sec;
	}
	return pts;
}

double get_video_clock(VideoState *is) {
	double delta;
	
	delta = (av_gettime() - is->video_current_pts_time) / 1000000.0;
	return is->video_current_pts + delta;
}

double get_external_clock(VideoState *is) {
	return av_gettime() / 1000000.0;
}

double get_master_clock(VideoState *is) {
	if (is->av_sync_type == AV_SYNC_VIDEO_MASTER) {
		return get_video_clock(is);
	} else if (is->av_sync_type == AV_SYNC_AUDIO_MASTER) {
		return get_audio_clock(is);
	} else {
		return get_external_clock(is);
	}
}

// Add or subtract samples to get a better sync, return new audio buffer size.
int synchronize_audio(VideoState *is, short *samples, int samples_size, double pts) {
	int n;
	double ref_clock;
	
	n = 2 * is->audio_st->codec->channels;
	
	if (is->av_sync_type != AV_SYNC_AUDIO_MASTER) {
		double diff, avg_diff;
		int wanted_size, min_size, max_size; //, nb_samples 
		
		ref_clock = get_master_clock(is);
		diff = get_audio_clock(is) - ref_clock;
		
		if (diff < AV_NOSYNC_THRESHOLD) {
			// Accumulate the diffs.
			is->audio_diff_cum = diff + is->audio_diff_avg_coef
			* is->audio_diff_cum;
			if (is->audio_diff_avg_count < AUDIO_DIFF_AVG_NB) {
				is->audio_diff_avg_count++;
			} else {
				avg_diff = is->audio_diff_cum * (1.0 - is->audio_diff_avg_coef);
				if (fabs(avg_diff) >= is->audio_diff_threshold) {
					wanted_size = samples_size + ((int) (diff * is->audio_st->codec->sample_rate) * n);
					min_size = samples_size * ((100 - SAMPLE_CORRECTION_PERCENT_MAX) / 100);
					max_size = samples_size * ((100 + SAMPLE_CORRECTION_PERCENT_MAX) / 100);
					if (wanted_size < min_size) {
						wanted_size = min_size;
					} else if (wanted_size > max_size) {
						wanted_size = max_size;
					}
					if (wanted_size < samples_size) {
						// Remove samples.
						samples_size = wanted_size;
					} else if (wanted_size > samples_size) {
						uint8_t *samples_end, *q;
						int nb;
						
						// Add samples by copying final sample.
						nb = (samples_size - wanted_size);
						samples_end = (uint8_t *) samples + samples_size - n;
						q = samples_end + n;
						while (nb > 0) {
							memcpy(q, samples_end, n);
							q += n;
							nb -= n;
						}
						samples_size = wanted_size;
					}
				}
			}
		} else {
			// Difference is too big, reset diff stuff.
			is->audio_diff_avg_count = 0;
			is->audio_diff_cum = 0;
		}
	}
	return samples_size;
}

int audio_decode_frame(VideoState *is, double *pts_ptr) {
	int len1, data_size = 0, n;
	AVPacket *pkt = &is->audio_pkt;
	double pts;
	
	for (;;) {
		while (is->audio_pkt_size > 0) {
			int got_frame = 0;
			len1 = avcodec_decode_audio4(is->audio_st->codec, &is->audio_frame, &got_frame, pkt);
			if (len1 < 0) {
				// if error, skip frame.
				is->audio_pkt_size = 0;
				break;
			}
			if (got_frame)
			{
				data_size =
				av_samples_get_buffer_size
				(
				 NULL,
				 is->audio_st->codec->channels,
				 is->audio_frame.nb_samples,
				 is->audio_st->codec->sample_fmt,
				 1
				 );
				memcpy(is->audio_buf, is->audio_frame.data[0], data_size);
			}
			is->audio_pkt_data += len1;
			is->audio_pkt_size -= len1;
			if (data_size <= 0) {
				// No data yet, get more frames.
				continue;
			}
			pts = is->audio_clock;
			*pts_ptr = pts;
			n = 2 * is->audio_st->codec->channels;
			is->audio_clock += (double)data_size /
			(double)(n * is->audio_st->codec->sample_rate);
			
			// We have data, return it and come back for more later.
			return data_size;
		}
		if (pkt->data)
			av_packet_unref(pkt);
		
		if (is->quit) {
			return -1;
		}
		// Next packet.
		if (packet_queue_get(&is->audioq, pkt, 1) < 0) {
			return -1;
		}
		is->audio_pkt_data = pkt->data;
		is->audio_pkt_size = pkt->size;
		// If update, update the audio clock w/pts.
		if (pkt->pts != AV_NOPTS_VALUE) {
			is->audio_clock = av_q2d(is->audio_st->time_base) * pkt->pts;
		}
	}
}

void audio_callback(void *userdata, Uint8 *stream, int len) {
	VideoState *is = (VideoState *)userdata;
	int len1, audio_size;
	double pts;
	
	while (len > 0) {
		if (is->audio_buf_index >= is->audio_buf_size) {
			// We have already sent all our data; get more.
			audio_size = audio_decode_frame(is, &pts);
			if (audio_size < 0) {
				// If error, output silence.
				is->audio_buf_size = 1024;
				memset(is->audio_buf, 0, is->audio_buf_size);
			} else {
				audio_size = synchronize_audio(is, (int16_t *)is->audio_buf, audio_size, pts);
				is->audio_buf_size = audio_size;
			}
			is->audio_buf_index = 0;
		}
		len1 = is->audio_buf_size - is->audio_buf_index;
		if (len1 > len) {
			len1 = len;
		}
		memcpy(stream, (uint8_t *) is->audio_buf + is->audio_buf_index, len1);
		len -= len1;
		stream += len1;
		is->audio_buf_index += len1;
	}
}

static Uint32 sdl_refresh_timer_cb(Uint32 interval, void *opaque) {
	SDL_Event event;
	event.type = FF_REFRESH_EVENT;
	event.user.data1 = opaque;
	SDL_PushEvent(&event);
	return 0; // 0 means stop timer.
}

// Schedule a video refresh in 'delay' ms.
static void schedule_refresh(VideoState *is, int delay) {
	SDL_AddTimer(delay, sdl_refresh_timer_cb, is);
}

void video_display(VideoState *is) {
	SDL_Rect rect;
	VideoPicture *vp;
	//AVFrame pict;
	float aspect_ratio;
	int w, h, x, y;
	//int i;
	
	vp = &is->pictq[is->pictq_rindex];
	if (vp->bmp) {
		if (is->video_st->codec->sample_aspect_ratio.num == 0) {
			aspect_ratio = 0;
		} else {
			aspect_ratio = av_q2d(is->video_st->codec->sample_aspect_ratio) * is->video_st->codec->width / is->video_st->codec->height;
		}
		if (aspect_ratio <= 0.0) {
			aspect_ratio = (float) is->video_st->codec->width / (float) is->video_st->codec->height;
		}
		h = screen->h;
		w = ((int) rint(h * aspect_ratio)) & -3;
		if (w > screen->w) {
			w = screen->w;
			h = ((int) rint(w / aspect_ratio)) & -3;
		}
		x = (screen->w - w) / 2;
		y = (screen->h - h) / 2;
		
		rect.x = x;
		rect.y = y;
		rect.w = w;
		rect.h = h;
		SDL_DisplayYUVOverlay(vp->bmp, &rect);
	}
}

void video_refresh_timer(void *userdata) {
	VideoState *is = (VideoState *)userdata;
	VideoPicture *vp;
	double actual_delay, delay, sync_threshold, ref_clock, diff;
	
	if (is->video_st) {
		if (is->pictq_size == 0) {
			schedule_refresh(is, 1);
		} else {
			vp = &is->pictq[is->pictq_rindex];
			
			is->video_current_pts = vp->pts;
			is->video_current_pts_time = av_gettime();
			
			delay = vp->pts - is->frame_last_pts; // The pts from last time.
			if (delay <= 0 || delay >= 1.0) {
				// iI incorrect delay, use previous one.
				delay = is->frame_last_delay;
			}
			// Save for next time.
			is->frame_last_delay = delay;
			is->frame_last_pts = vp->pts;
			
			// Update delay to sync to audio if not master source.
			if (is->av_sync_type != AV_SYNC_VIDEO_MASTER) {
				ref_clock = get_master_clock(is);
				diff = vp->pts - ref_clock;
				
				// Skip or repeat the frame. Take delay into account FFPlay still doesn't "know if this is the best guess.".
				sync_threshold = (delay > AV_SYNC_THRESHOLD) ? delay : AV_SYNC_THRESHOLD;
				if (fabs(diff) < AV_NOSYNC_THRESHOLD) {
					if (diff <= -sync_threshold) {
						delay = 0;
					} else if (diff >= sync_threshold) {
						delay = 2 * delay;
					}
				}
			}
			
			is->frame_timer += delay;
			// Computer the REAL delay.
			actual_delay = is->frame_timer - (av_gettime() / 1000000.0);
			if (actual_delay < 0.010) {
				// Really it should skip the picture instead.
				actual_delay = 0.010;
			}
			schedule_refresh(is, (int)(actual_delay * 1000 + 0.5));
			
			// Show the picture!
			video_display(is);
			
			// Update queue for next picture!
			if (++is->pictq_rindex == VIDEO_PICTURE_QUEUE_SIZE) {
				is->pictq_rindex = 0;
			}
			SDL_LockMutex(is->pictq_mutex);
			is->pictq_size--;
			SDL_CondSignal(is->pictq_cond);
			SDL_UnlockMutex(is->pictq_mutex);
		}
	} else {
		schedule_refresh(is, 100);
	}
}

void alloc_picture(void *userdata) {
	VideoState *is = (VideoState *)userdata;
	VideoPicture *vp;
	
	vp = &is->pictq[is->pictq_windex];
	if (vp->bmp) {
		// We already have one make another, bigger/smaller.
		SDL_FreeYUVOverlay(vp->bmp);
	}
	// Allocate a place to put our YUV image on that screen.
	vp->bmp = SDL_CreateYUVOverlay(is->video_st->codec->width, is->video_st->codec->height, SDL_YV12_OVERLAY, screen);
	vp->width = is->video_st->codec->width;
	vp->height = is->video_st->codec->height;
	
	SDL_LockMutex(is->pictq_mutex);
	vp->allocated = 1;
	SDL_CondSignal(is->pictq_cond);
	SDL_UnlockMutex(is->pictq_mutex);
	
}

int queue_picture(VideoState *is, AVFrame *pFrame, double pts) {
	VideoPicture *vp;
	AVFrame pict;
	
	// Wait until we have space for a new pic.
	SDL_LockMutex(is->pictq_mutex);
	while (is->pictq_size >= VIDEO_PICTURE_QUEUE_SIZE && !is->quit) {
		SDL_CondWait(is->pictq_cond, is->pictq_mutex);
	}
	SDL_UnlockMutex(is->pictq_mutex);
	
	if (is->quit) {
		return -1;
	}
	
	// windex is set to 0 initially.
	vp = &is->pictq[is->pictq_windex];
	
	// Allocate or resize the buffer!.
	if (!vp->bmp || vp->width != is->video_st->codec->width || vp->height != is->video_st->codec->height) {
		SDL_Event event;
		
		vp->allocated = 0;
		// We have to do it in the main thread.
		event.type = FF_ALLOC_EVENT;
		event.user.data1 = is;
		SDL_PushEvent(&event);
		
		// wait until we have a picture allocated.
		SDL_LockMutex(is->pictq_mutex);
		while (!vp->allocated && !is->quit) {
			SDL_CondWait(is->pictq_cond, is->pictq_mutex);
		}
		SDL_UnlockMutex(is->pictq_mutex);
		if (is->quit) {
			return -1;
		}
	}
	// We have a place to put our picture on the queue.
	// If we are skipping a frame, do we set this to null but still return vp->allocated = 1?	
	if (vp->bmp) {
		
		SDL_LockYUVOverlay(vp->bmp);
		
		// Point pict at the queue.
		pict.data[0] = vp->bmp->pixels[0];
		pict.data[1] = vp->bmp->pixels[2];
		pict.data[2] = vp->bmp->pixels[1];
		
		pict.linesize[0] = vp->bmp->pitches[0];
		pict.linesize[1] = vp->bmp->pitches[2];
		pict.linesize[2] = vp->bmp->pitches[1];
		
		// Convert the image into YUV format that SDL uses.
		sws_scale(is->sws_ctx, (uint8_t const * const *) pFrame->data, pFrame->linesize, 0, is->video_st->codec->height, pict.data, pict.linesize);
		
		SDL_UnlockYUVOverlay(vp->bmp);
		vp->pts = pts;
		
		// Now we inform our display thread that we have a pic ready.
		if (++is->pictq_windex == VIDEO_PICTURE_QUEUE_SIZE) {
			is->pictq_windex = 0;
		}
		SDL_LockMutex(is->pictq_mutex);
		is->pictq_size++;
		SDL_UnlockMutex(is->pictq_mutex);
	}
	return 0;
}

double synchronize_video(VideoState *is, AVFrame *src_frame, double pts) {
	double frame_delay;
	
	if (pts != 0) {
		// If we have pts, set video clock to it.
		is->video_clock = pts;
	} else {
		// If we aren't given a pts, set it to the clock.
		pts = is->video_clock;
	}
	// Update the video clock.
	frame_delay = av_q2d(is->video_st->codec->time_base);
	// If we are repeating a frame, adjust clock accordingly.
	frame_delay += src_frame->repeat_pict * (frame_delay * 0.5);
	is->video_clock += frame_delay;
	return pts;
}

uint64_t global_video_pkt_pts = AV_NOPTS_VALUE;

// These are called whenever we allocate a frame buffer. We use this to store the global_pts in a frame at the time it is allocated.
int our_get_buffer(struct AVCodecContext *c, AVFrame *pic, int flags) {
	int ret = avcodec_default_get_buffer2(c, pic, 0);
	uint64_t *pts = av_malloc(sizeof(uint64_t));
	*pts = global_video_pkt_pts;
	pic->opaque = pts;
	return ret;
}
// void our_release_buffer(struct AVCodecContext *c, AVFrame *pic) {
//   if (pic) av_freep(&pic->opaque);
//   avcodec_default_release_buffer(c, pic);
// }

int video_thread(void *arg) {
	VideoState *is = (VideoState *)arg;
	AVPacket pkt1, *packet = &pkt1;
	int frameFinished;
	AVFrame *pFrame;
	double pts;
	
	pFrame = av_frame_alloc();
	
	for (;;) {
		if (packet_queue_get(&is->videoq, packet, 1) < 0) {
			// Means we quit getting packets.
			break;
		}
		pts = 0;
		
		// Save global pts to be stored in pFrame in first call.
		global_video_pkt_pts = packet->pts;
		// Decode video frame.
		avcodec_decode_video2(is->video_st->codec, pFrame, &frameFinished, packet);
		if (packet->dts == AV_NOPTS_VALUE && pFrame->opaque && *(uint64_t*)pFrame->opaque != AV_NOPTS_VALUE) {
			pts = *(uint64_t *)pFrame->opaque;
		} else if (packet->dts != AV_NOPTS_VALUE) {
			pts = packet->dts;
		} else {
			pts = 0;
		}
		pts *= av_q2d(is->video_st->time_base);
		
		// Did we get a video frame?.
		if (frameFinished) {
			pts = synchronize_video(is, pFrame, pts);
			if (queue_picture(is, pFrame, pts) < 0) {
				break;
			}
		}
		av_packet_unref(packet);
	}
	av_free(pFrame);
	return 0;
}

int stream_component_open(VideoState *is, int stream_index) {
	AVFormatContext *pFormatCtx = is->pFormatCtx;
	AVCodecContext *codecCtx = NULL;
	AVCodec *codec = NULL;
	AVDictionary *optionsDict = NULL;
	SDL_AudioSpec wanted_spec, spec;
	
	if (stream_index < 0 || stream_index >= pFormatCtx->nb_streams) {
		return -1;
	}
	
	// Get a pointer to the codec context for the video stream.
	codecCtx = pFormatCtx->streams[stream_index]->codec;
	
	if (codecCtx->codec_type == AVMEDIA_TYPE_AUDIO) {
		// Set audio settings from codec info.
		wanted_spec.freq = codecCtx->sample_rate;
		wanted_spec.format = AUDIO_S16SYS;
		wanted_spec.channels = codecCtx->channels;
		wanted_spec.silence = 0;
		wanted_spec.samples = SDL_AUDIO_BUFFER_SIZE;
		wanted_spec.callback = audio_callback;
		wanted_spec.userdata = is;
		
		if (SDL_OpenAudio(&wanted_spec, &spec) < 0) {
			fprintf(stderr, "SDL_OpenAudio: %s\n", SDL_GetError());
			return -1;
		}
		is->audio_hw_buf_size = spec.size;
	}
	codec = avcodec_find_decoder(codecCtx->codec_id);
	if (!codec || (avcodec_open2(codecCtx, codec, &optionsDict) < 0)) {
		fprintf(stderr, "Unsupported codec!\n");
		return -1;
	}
	
	switch (codecCtx->codec_type) {
		case AVMEDIA_TYPE_AUDIO:
			is->audioStream = stream_index;
			is->audio_st = pFormatCtx->streams[stream_index];
			is->audio_buf_size = 0;
			is->audio_buf_index = 0;
			
			// Averaging filter for audio sync.
			is->audio_diff_avg_coef = exp(log(0.01 / AUDIO_DIFF_AVG_NB));
			is->audio_diff_avg_count = 0;
			// Correct audio only if larger error than this.
			is->audio_diff_threshold = 2.0 * SDL_AUDIO_BUFFER_SIZE / codecCtx->sample_rate;
			
			memset(&is->audio_pkt, 0, sizeof(is->audio_pkt));
			packet_queue_init(&is->audioq);
			SDL_PauseAudio(0);
			break;
		case AVMEDIA_TYPE_VIDEO:
			is->videoStream = stream_index;
			is->video_st = pFormatCtx->streams[stream_index];
			
			is->frame_timer = (double)av_gettime() / 1000000.0;
			is->frame_last_delay = 40e-3;
			is->video_current_pts_time = av_gettime();
			
			packet_queue_init(&is->videoq);
			is->video_tid = SDL_CreateThread(video_thread, is);
			is->sws_ctx = sws_getContext(is->video_st->codec->width, is->video_st->codec->height, is->video_st->codec->pix_fmt, is->video_st->codec->width, is->video_st->codec->height, AV_PIX_FMT_YUV420P, SWS_BILINEAR, NULL, NULL, NULL);
			codecCtx->get_buffer2 = our_get_buffer;
			// codecCtx->release_buffer = our_release_buffer;
			break;
		default:
			break;
	}
	
	return 0;
}

int decode_interrupt_cb(void *opaque) {
	return (global_video_state && global_video_state->quit);
}

int decode_thread(void *arg) {
	VideoState *is = (VideoState *)arg;
	AVFormatContext *pFormatCtx = NULL;
	AVPacket pkt1, *packet = &pkt1;
	
	AVDictionary *io_dict = NULL;
	AVIOInterruptCB callback;
	
	int video_index = -1;
	int audio_index = -1;
	int i;
	
	is->videoStream=-1;
	is->audioStream=-1;
	
	global_video_state = is;
	// Will interrupt blocking functions if we quit!.
	callback.callback = decode_interrupt_cb;
	callback.opaque = is;
	if (avio_open2(&is->io_context, is->filename, 0, &callback, &io_dict)) {
		fprintf(stderr, "Unable to open I/O for %s\n", is->filename);
		return -1;
	}
	
	// Open video file.
	if (avformat_open_input(&pFormatCtx, is->filename, NULL, NULL) != 0)
		return -1; // Couldn't open file.
	
	is->pFormatCtx = pFormatCtx;
	
	// Retrieve stream information.
	if (avformat_find_stream_info(pFormatCtx, NULL) < 0) {
		return -1; // Couldn't find stream information.
	}
	
	// Dump information about file onto standard error.
	av_dump_format(pFormatCtx, 0, is->filename, 0);
	
	// Find the first video stream.
	for (i = 0; i < pFormatCtx->nb_streams; i++) {
		if (pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO && video_index < 0) {
			video_index = i;
		}
		if (pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO && audio_index < 0) {
			audio_index = i;
		}
	}
	if (audio_index >= 0) {
		stream_component_open(is, audio_index);
	}
	if (video_index >= 0) {
		stream_component_open(is, video_index);
	}   
	
	if (is->videoStream < 0 || is->audioStream < 0) {
		fprintf(stderr, "%s: could not open codecs\n", is->filename);
		goto fail;
	}
	
	// Main decode loop.
	for (;;) {
		if (is->quit) {
			break;
		}
		// Seek stuff goes here.
		if (is->audioq.size > MAX_AUDIOQ_SIZE ||
		   is->videoq.size > MAX_VIDEOQ_SIZE) {
			SDL_Delay(10);
			continue;
		}
		if (av_read_frame(is->pFormatCtx, packet) < 0) {
			if (is->pFormatCtx->pb->error == 0) {
				SDL_Delay(100); // No error; wait for user input.
				continue;
			} else {
				break;
			}
		}
		// Is this a packet from the video stream?.
		if (packet->stream_index == is->videoStream) {
			packet_queue_put(&is->videoq, packet);
		} else if (packet->stream_index == is->audioStream) {
			packet_queue_put(&is->audioq, packet);
		} else {
			av_packet_unref(packet);
		}
	}
	// All done - wait for it.
	while (!is->quit) {
		SDL_Delay(100);
	}
	
fail:
	{
		SDL_Event event;
		event.type = FF_QUIT_EVENT;
		event.user.data1 = is;
		SDL_PushEvent(&event);
	}
	return 0;
}

int main(int argc, char *argv[]) {
	SDL_Event event;
	VideoState *is;
	
	is = av_mallocz(sizeof(VideoState));
	
	if (argc < 2) {
		fprintf(stderr, "Usage: test <file>\n");
		exit(1);
	}
	// Register all formats and codecs.
	av_register_all();
	
	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER)) {
		fprintf(stderr, "Could not initialize SDL - %s\n", SDL_GetError());
		exit(1);
	}
	
	// Make a screen to put our video.
#ifndef __DARWIN__
	screen = SDL_SetVideoMode(640, 480, 0, 0);
#else
	screen = SDL_SetVideoMode(640, 480, 24, 0);
#endif
	if (!screen) {
		fprintf(stderr, "SDL: could not set video mode - exiting\n");
		exit(1);
	}
	
	av_strlcpy(is->filename, argv[1], 1024);
	
	is->pictq_mutex = SDL_CreateMutex();
	is->pictq_cond = SDL_CreateCond();
	
	schedule_refresh(is, 40);
	
	is->av_sync_type = DEFAULT_AV_SYNC_TYPE;
	is->parse_tid = SDL_CreateThread(decode_thread, is);
	if (!is->parse_tid) {
		av_free(is);
		return -1;
	}
	for (;;) {
		SDL_WaitEvent(&event);
		switch (event.type) {
			case FF_QUIT_EVENT:
			case SDL_QUIT:
				is->quit = 1;
				// If the video has finished playing, then both the picture and audio queues are waiting for more data.  Make them stop waiting and terminate normally.
				SDL_CondSignal(is->audioq.cond);
				SDL_CondSignal(is->videoq.cond);
				SDL_Quit();
				exit(0);
				break;
			case FF_ALLOC_EVENT:
				alloc_picture(event.user.data1);
				break;
			case FF_REFRESH_EVENT:
				video_refresh_timer(event.user.data1);
				break;
			default:
				break;
		}
	}
	return 0;
	
}
